The present invention relates generally to harvesting bone. More specifically, it concerns a bone-harvesting method and a to-be-used-therewith hollow, generally cylindrical coring drill bit and cooperative fitting assembly wherein the drill bit includes a locking end and cutting end having a cutting edge and an adjacent opening, the drill bit providing for the morselized removal of bone from a donor site and its collection within the drill bit's hollow shank region for transplantation at a donee site.
Bone is harvested for transplantation or grafting generally by one of two methods: it is removed in the form of a plug or it is removed in particulate form. In accordance with the latter, bone harvesting is performed by using a drill which bores and chips its way into the bone for the purpose of removing part of it in a granulated or morselized form, which is then transplanted or grafted onto another bony area. The granulated or morselized form is best for transplanting because it can be packed into another area where bone has been eroded, for example in an arthritic joint or other area in which bone has been diminished. Typical ways that bone may be removed or harvested is by using an osteotome which is a fine-bladed chisel used to remove a wedge of bone for transfer to another area. The second way is by use of a chipping-type drill, as in the present invention.
U.S. Pat. No. 3,112,743, entitled METHOD FOR TREATMENT OF BONE FRACTURES, discloses an axially and radially ported chipping-type bit used to drill holes in bones in preparation for injection of polyurethane foam into the medullary canal for treatment of broken or fractured bones. The disclosed bit has a tapered tip of a half-conical shape exposing symmetric clockwise- and counterclockwise-rotational cutting edges. The tapered tip also has an end opening defined on the tapered surface to guide pulverized bone fragments away from a connected hollow tube through which the polyurethane is to be injected. The end opening within the bit also allows the injected polyurethane to spread radially as well as axially through the medullary canal. Because the drill bit is meant for drilling holes in bone and not for collection of bone fragments for harvesting, it is structured to allow polyurethane to be injected out of the bit rather than letting harvested fragments in. Thus, its cutting head is sharply pointed at an acute angle, thereby permitting relatively shallow-angle drilling and injecting, i.e. drilling and injecting with the long axis of the drill bit at an acute angle to the plane of the bone's surface.